Acetylenic alcohols and ethers as accelerators for hydrosilation

ABSTRACT

A hydrosilation process where a silicon hydride is reacted with an unsaturated reactant in the presence of a platinum catalyst and an accelerator selected from a group consisting of acetylenic alcohols, silated acetylenic alcohols, and acetylenic ethers. The accelerators are especially useful for the hydrosilation of unsaturated reactants where the unsaturation is in the internal portion of the reactant&#39;s structure, for example, as in cyclopentene and cyclohexene. The unsaturated ketone accelerators are effective in the presence or absence of oxygen.

BACKGROUND OF INVENTION

The present invention is a hydrosilation process where a silicon hydrideis reacted with an unsaturated reactant in the presence of a platinumcatalyst and an accelerator selected from a group consisting ofacetylenic alcohols, silated acetylenic alcohols, and acetylenic ethers.The accelerators are especially useful for the hydrosilation ofunsaturated reactants where the unsaturation is in the internal portionof the reactant's structure, for example, as in cyclopentene andcyclohexene. The unsaturated ketone accelerators are effective in thepresence or absence of oxygen.

It is known in the art to produce organosilicon compounds by reacting asilicon hydride containing compound with an unsaturated organic compoundin the presence of a catalyst. This reaction is typically referred to ashydrosilation or hydrosilylation. Typically the catalyst is platinummetal on a support, a platinum compound generally in a solvent, or aplatinum complex.

In Speier et al., U.S. Pat. No. 2,823,218, a method for the productionof organosilicon compounds by reacting an Si-H with a compoundcontaining aliphatic carbon atoms linked by multiple bonds in thepresence of chloroplatinic acid is taught. Lamoreaux, U.S. Pat. No.3,220,972, teaches a similar process, however the catalyst is a reactionproduct of chloroplatinic acid.

One of the major problems known in the art with hydrosilation reactionsis the de-activation of the catalyst prior to the completion of thereaction. One method for reactivation of the catalyst has been to exposethe reaction mixture to oxygen. For example, Onopchenko et al., U.S.Pat. No. 4,578,497, teaches the use of an oxygenated platinum containingcatalyst for use in hydrosilating alkylsilanes. Kleyer et al., U.S. Pat.No. 5,359,111, discloses a method for controlling hydrosilation reactionmixtures by controlling the solution concentration of oxygen in thereaction mixture, relative to the platinum present in the reactionmixture.

In addition to the problem of de-activation of the platinum catalyst,hydrosilation processes taught in the art are not particularly effectivein hydrosilating internal unsaturated bonds in organic molecules. Thepresent inventors have unexpectedly discovered that acetylenic alcohols,silated acetylenic alcohols, and acetylenic ethers can act asaccelerators for platinum catalyzed hydrosilation processes. Theaccelerators can improve yield of the process in the presence or absenceof oxygen and are particularly effective in facilitating thehydrosilation of internal unsaturated bonds of organic molecules.

SUMMARY OF INVENTION

The present invention is a hydrosilation process where a silicon hydrideis reacted with an unsaturated reactant in the presence of a platinumcatalyst and an accelerator selected from a group consisting ofacetylenic alcohols, silated acetylenic alcohols, and acetylenic ethers.The accelerators are especially useful for the hydrosilation ofunsaturated reactants where the unsaturation is in the internal portionof the reactant's structure, for example, as in cyclopentene andcyclohexene. The unsaturated ketone accelerators are effective in thepresence or absence of oxygen.

DESCRIPTION OF INVENTION

The present invention is a hydrosilation process where a silicon hydrideis reacted with an unsaturated reactant in the presence of a platinumcatalyst and a novel accelerator. The hydrosilation process comprises:contacting

(A) a silicon hydride described by formula

    R.sup.1.sub.a H.sub.b SiCl.sub.4-a-b,                      (1)

where each R¹ is independently selected from a group consisting ofalkyls comprising one to 20 carbon atoms, cycloalkyls comprising four to12 carbon atoms, and aryls; a=0 to 3, b=1 to 3, and a+b=1 to 4; and

(B) an unsaturated reactant selected from a group consisting of

(i) substituted and unsubstituted unsaturated organic compounds,

(ii) silicon compounds comprising substituted or unsubstitutedunsaturated organic substituents, and

(iii) mixtures of (i) and (ii);

in the presence of a platinum catalyst selected from a group consistingof platinum compounds and platinum complexes, and an acceleratorselected from a group consisting of acetylenic alcohols described byformulas ##STR1## silated acetylenic alcohols described by formulas##STR2## acetylenic ethers described by formulas ##STR3## where R² isselected from a group consisting of hydrogen, hydroxyl, substituted andunsubstituted alkyls comprising one to 20 carbon atoms, and substitutedand unsubstituted alkoxys comprising one to 20 carbon atoms, each R³ isindependently selected from a group consisting of hydrogen, alkylscomprising one to 20 carbon atoms, cycloalkyls comprising four to 20carbon atoms, and aryls; each R⁴ is an independently selected alkyl orcycloalkyl comprising no more than 20 carbon atoms, R⁵ is selected froma group consisting of monovalent hydrocarbon radicals comprising one to20 carbon atoms and heterocyclic hydrocarbon radicals having a carbon tooxygen bond, each R⁶ is independently selected from a group consistingof hydrogen and R¹, c=0 to 3, d=0 to 3, c+d=0 to 3, e=1 to 4, f=0 to 10,and n=4 to 12.

The contacting of the silicon hydride with the unsaturated reactant canbe effected in standard type reactors for conducting hydrosilationprocesses. The contact and reaction may be run as a continuous,semi-continuous, or batch reaction.

Silicon hydrides which are useful in the present process are describedby formula (1), where each R¹ is independently selected from a groupconsisting of alkyls comprising one to 20 carbon atoms, cycloalkylscomprising four to 12 carbon atoms, and aryls; a=0 to 3, b=1 to 3, anda+b=1 to 4. R¹ can be a substituted or unsubstituted alkyl, cycloalkyl,or aryl as described.

In formula (1) it is preferred that each R¹ be independently selectedfrom a group consisting of alkyls comprising about one to six carbonatoms. Even more preferred is when each R¹ is methyl. Examples, ofsilicon hydrides described by formula (1) which may be useful in thepresent process include trimethylsilane, dimethylsilane, triethylsilane,dichlorosilane, trichlorosilane, methyldichlorosilane,dimethylchlorosilane, ethyldichlorosilane, cyclopentyldichlorosilane,methylphenylchlorosilane, and (3,3,3-trifluoropropyl)dichlorosilane.Examples of preferred silicon hydrides described by formula (1) includemethyldichlorosilane and dichlorosilane.

The silicon hydride is contacted with an unsaturated reactant selectedfrom a group consisting of (i) substituted and unsubstituted unsaturatedorganic compounds, (ii) silicon compounds comprising substituted andunsubstituted unsaturated organic substituents, and (iii) mixtures of(i) and (ii). For purpose of this invention, "unsaturated" means thatthe compound contains at least one carbon-carbon double bond.

More specific examples of the unsaturated reactants useful in thepresent process include unsubstituted cycloalkene compounds comprisingat least four carbon atoms, substituted cycloalkene compounds comprisingat least four carbon atoms, linear alkene compounds comprising about twoto 30 carbon atoms, branched alkene compounds comprising four to about30 carbon atoms, and mixtures of two or more of any of the above.

The substituted and unsubstituted cycloalkene compounds useful in thepresent process are those containing one or more unsaturatedcarbon-carbon bonds in the ring. The unsubstituted cycloalkene compoundsmay be, for example, cyclobutene, cyclopentene, cyclohexene,cycloheptene, cyclooctene, cyclopentadiene, 1,3-cyclohexadiene, and1,3,5-cycloheptatriene. Substituted unsaturated compounds useful in thepresent invention may be, for example, 3-methylcyclopentene,3-chlorocyclobutene, 4-phenylcyclohexene, and 3-methylcyclopentadiene.The preferred cycloalkene compounds are cyclohexene and cyclopentene,with cyclohexene being the most preferred.

Other unsaturated organic compounds useful in the present process arelinear and branched alkenyl compounds including, for example, compoundswith terminal unsaturation such as 1-hexene and 1,5-hexadiene, compoundswith internal unsaturation such as trans-2-hexene, and unsaturated arylcontaining compounds such as styrene and α-methylstyrene.

The unsaturated reactants may also comprise halogen, oxygen in the formof acids, anhydrides, alcohols, esters, and ethers; and nitrogen. Two ormore of the above described unsaturated organic compounds may be used inthe present process.

The unsaturated organic compounds comprising halogen may include, forexample, vinyl chloride, allyl chloride, allyl bromide, allyl iodide,allyl bromide, methallyl chloride, trichloroethylene,tetrachloroethylene, tetrafluoroethylene, chloroprene, vinylidenechloride, and dichlorostyrene.

Suitable unsaturated organic compounds comprising oxygen can include,for example, ethers such as allyl and vinyl ethers; alcohols such asallyl alcohol (vinyl carbinol), methylvinylcarbinol andethynyldimethyl-carbinol; acids such as acrylic, methacrylic,vinylacetic, oleic, sorbic, and linolenic; and esters such as vinylacetate, allyl acetate, butenyl acetate, allyl stearate, methylacrylate,ethylcrotonate, dially succinate and dially phthalate. Suitable nitrogencontaining unsaturated organic compounds include, for example, indigo,indole, acrylonitrile, and allyl cyanide.

Specifically included within the definition of unsaturated organiccompounds are those substituted by organofunctional moieties such as

CH₂ ═CHCH₂ OC(O)C(CH₃)═CH₂,

CH₂ ═CHCH₂ NHCH₂ CH₂ NH₂,

CH₂ ═CHCH₂ NH₂, ##STR4## CH₂ ═CHCH₂ SH CH₂ ═CHSi{O(CH₂)₂ OCH₃ }₃,

CH₂ ═CHCH₂ N(HCl)HCH₂ CH₂ NHCH₂ (C₆ H₄)CH═CH₂,

and other similar such compounds.

The unsaturated organic compound can be a silicon compound comprisingsubstituted and unsubstituted organic substituents as described by, forexample, formulas (CH₂ ↑CH(CH₂)g)_(h) R¹ _(i) Si(OR¹)_(4-h-i) and (CH₂═CH(CH₂)_(g))_(h) R¹ _(i) SiSl_(4-h-i), where R¹ is as previouslydescribed, g=0 to 12, h=1 to 3, i=0 to 3, and f+g=1 to 4.

Prior to contact of the silicon hydride with the unsaturated reactant,it may be preferable to treat or purify the unsaturated reactant.Methods useful for treating or purifying the unsaturated reactants arethose known in the art for treating or purifying unsaturated organiccompounds and include but are not limited to distillation and treatmentwith an adsorbent such as activated alumina or molecular sieves.

The relative amounts of silicon hydride and unsaturated reactant used inthe present process can be varied within wide limits. Although oneunsaturated carbon-carbon linkage per silicon bonded hydrogen atom isstoichiometric, there is no requirement that the process be run understoichiometric conditions. Generally, it is preferred that the processbe run with a stoichiometric excess of silicon hydride. Preferred iswhen the process is run with about 0.1 to ten percent stoichiometricexcess of silicon hydride. However in some situations for safety reasonsit may be preferred to run the process with an excess of unsaturatedreactant, for example when the silicon hydride is dichlorosilane.

The silicon hydride and unsaturated reactant are contacted in thepresence of a platinum catalyst selected from a group consisting ofplatinum compounds and platinum complexes. Any platinum containingmaterial which effects the reaction between the silicon hydride and anunsaturated carbon-carbon bond of the unsaturated organic compound isuseful in the present invention. Examples of platinum catalysts usefulin the present process are described, for example, in Onopchenko, U.S.Pat. No. 4,578,497; Lamoreaux, U.S. Pat. No. 3,220,972; and Speier, U.S.Pat. No. 2,823,218 all of which are hereby incorporated herein byreference.

The platinum catalyst can be, for example, chloroplatinic acid,chloroplatinic acid hexahydrate, Karstedt's catalyst (i.e. a complex ofchloroplatinic acid with sym-divinyltetramethyldisiloxane),dichloro-bis(triphenylphosphine)platinum(II),cis-dichloro-bis(acetonitrile)platinum(II),dicarbonyldichloroplatinum(II), platinum chloride, and platinum oxide.

A preferred platinum catalyst is selected from the group consisting ofchloroplatinic acid, chloroplatinic acid hexahydrate, and platinumvinylsiloxane complexes such as a neutralized complex of chloroplatinicacid or platinum dichloride with sym-divinyltetramethyldisiloxane.

Generally, those concentrations of platinum catalyst which provide aboutone mole of platinum per billion moles of unsaturated carbon-carbonbonds added to the process by the unsaturated reactant may be useful inthe present process. Concentrations of platinum catalyst providing ashigh as about one mole of platinum per one thousand moles of unsaturatedcarbon-carbon bonds added to the process by the unsaturated reactant maybe useful. Higher concentrations of platinum may be used if desired. Apreferred concentration of platinum catalyst is that providing about oneto 1000 moles of platinum per 1×10⁶ moles of unsaturated carbon-carbonbonds provided to the process by the unsaturated reactant.

The platinum catalyst may be dissolved in a solvent for ease of handlingand to facilitate measuring the small amounts typically needed. Suitablesolvents include, for example, non-polar hydrocarbon solvents such asbenzene, toluene, and xylene and polar solvents such as alcohols,ketones, glycols, and esters.

The present process is carried out in the presence of an acceleratorselected from a group as described above by formulas (2) through (9).The substituent R² is selected from a group consisting of hydrogen,hydroxyl, substituted and unsubstituted alkyls comprising one to 20carbon atoms, and substituted and unsubstituted alkoxys comprising oneto 20 carbon atoms. Preferred is when R² is selected from a groupconsisting of hydrogen and alkyls comprising about one to about sixcarbon atoms. Substituent R² can be a substituted alkyl, for example,hydroxyethyl, 2-ethoxyethyl, and 1-methyl-1-hydroxyethyl. R² can be, forexample, hydrogen, methyl, ethyl, propyl, iso-butyl, hydroxyethyl,1-methyl-l-hydroxyethyl, and hexyl. Preferred is when R² is hydrogen.Each substituent R³ is independently selected from a group consisting ofhydrogen, alkyls comprising one to 20 carbon atoms, cycloalkylscomprising four to 20 carbon atoms, and aryls. R³ can be, for example,hydrogen, methyl, ethyl, propyl, iso-butyl, cyclopentyl, cyclohexyl, andphenyl. Preferred is when each R³ is independently selected from a groupconsisting of hydrogen, alkyls comprising one to 6 carbon atoms, andphenyl. Each substituent R⁴ is an independently selected alkyl orcycloalkyl comprising no more than 20 carbon atoms. Preferred is when R⁴is selected from a group consisting of methyl and cyclopentyl. R⁵ isselected from a group comprising monovalent hydrocarbon radicalscomprising one to 20 carbon atoms and heterocyclic hydrocarbon radicalshaving a carbon to oxygen bond. R⁵ can be, for example, alkyls such asmethyl, ethyl, tert-butyl; cycloalkyls such as cyclopentyl andcyclohexyl; aryls such as phenyl and naphthyl; and heterocyclichydrocarbons such as tetrahydrofuranyl. Each substituent R⁶ isindependently selected from a group consisting of hydrogen and R¹ aspreviously described. Preferred is when R⁶ is hydrogen.

In the silated acetylenic alcohols described by formulas (6) and (7), ccan have a value of zero to three, d can have a value of zero to three,and c plus d can have a value of zero to three. In formula (6), e canhave a value of one to four. Preferred is when e has a value of one.

In the acetylenic alcohols described by formulas (3) and (5), n can havea value of four to 12. Preferred is when n has a value of four or five.

In the acetylenic alcohols described by formulas (2), (3), (6), and (8),f can have a value of zero to about ten. Preferred is when f is a valueof zero to about four.

A preferred accelerator for use in the present process is selected froma group consisting of 2-methyl-3-butyn-2-ol, silated2-methyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, and3,5-dimethyl-1-hexyn-3-ol.

An effective concentration of the accelerator is added to the presentprocess, where an effective concentration is one that facilitatesinitiation of the reaction between the silicon hydride and theunsaturated organic compound, accelerates the rate of the reaction, orreduces loss of reactivity of the catalyst in the process. A usefuleffective concentration of the accelerator is generally within a rangeof about 0.01 to 20 weight percent of the weight of the unsaturatedreactant. Preferred is when the accelerator is about 0.1 to ten weightpercent of the weight of the unsaturated reactant. The accelerator maybe added to the process as a pre-mix with the platinum catalyst orseparately.

The temperature at which the present process can be conducted cangenerally be within a range of about -10° C. to 220° C. It is preferredto conduct the process at a temperature within a range of about 15° C.to 170° C. The most preferred temperature for conducting the process iswithin a range of about 30° C. to 150° C.

The following examples are provided to illustrate the present invention.These examples are not intended to limit the claims herein.

EXAMPLE 1

A variety of acetylenic alcohols, silated alcohols, and acetylenicethers were evaluated for their ability to accelerate the reaction ofmethyldichlorosilane with cyclohexene in the presence of a platinumcatalyst.

A stock mixture was prepared in an argon purged and blanketed bottle.The stock mixture comprised four molar percent excess ofmethyldichlorosilane in cyclohexene which had been treated with 13Xmolecular sieves. About 6×10⁻⁵ moles of platinum, as a platinumdivinylsiloxane complex, per mole, of cyclohexene was added to the stockmixture. Aliquots of this catalyzed stock solution were then transferredto argon-purged glass tubes which contained accelerators of thestructures provided in Table 1 at a concentration of 1 weight percent ofthe cyclohexene added to the tube. The tubes were heat sealed underargon purge and heated at 80° C. for three hours. At the end of threehours the tubes were cooled and the contents analyzed by gaschromatography using a thermal conductivity detector (GC-TC). Theresults of this analysis are reported in Tables 1 and 2 as thenormalized area percent of methyl(cyclohexyl)dichlorosilane (MeC_(H)SiCl₂) under the GC-TC trace. The data was normalized by using the areaunder the GC-TC trace minus the area of the cyclohexene as 100 percent.In the Tables, the heading "Formula Type" refers to the formulas asnumbered in the specification.

                  TABLE 1                                                         ______________________________________                                        Acetylenic Alcohols and Ethers as Accelerators For Platinum                   Catalyzed Addition of MeHSiCl.sub.2 to Cyclohexene                            Formula     Structure                                                         Type   Type     R.sup.2  R.sup.3                                                                            R.sup.3                                                                            R.sup.5                                                                            n   Area %                            ______________________________________                                        Alcohol                                                                              (2)      H        H    H    --   --  87.2                                     (2)      H        H    Me   --   --  98.5                                     (2)      Et       H    H    --   --  94.9                                     (2)      H        H    Ph   --   --  85.8                                     (2)      H        Me   Me   --   --  98.4                                     (2)      H        Me   i-bu --   --  99.7                                     (2)      HO--Et   Me   Me   --   --  98.5                                     (4)      --       Me   Me   --   --  95.4                                     (3)      H        --   --   --   5   99.5                                     (3)      Me       --   --   --   5   70.9                                     (3)      Et       --   --   --   4   86.5                                     (5)      --       --   --   --   5   70.2                              Ether  (8)      H        Me   Me   THF  --  84.7                              Blank (Ave. n = 5)                                                                        --       --     --   --   --  35.6                                ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Silated Acetylenic Alcohol Accelerators for Platinum                          Catalyzed Addition of MeHSiCl.sub.2 to Cyclohexene                            Formula                                                                              Structure                                                              Type   R.sup.2                                                                              R.sup.3                                                                              R.sup.3                                                                              R.sup.4                                                                            c    d   Area (%)                            ______________________________________                                        (6)    H      Me     Me     Me   3    0   98.2                                       H      Me     Me     --   0    1   78.4                                       H      Me     Me     --   0    0   51.3                                ______________________________________                                    

In Tables 1 and 2, Me is methyl, Et is ethyl, Ph is phenyl, i-bu isisobutyl, HO-Et is 1-methyl-1-hydroxyethyl, and THF istetrahydrofuranyl.

EXAMPLE 2

The ability of 2-methyl-3-butyn-2-ol (MBO) to accelerate the reaction ofdichlorosilane with cyclopentene in the presence of a platinum catalystwas evaluated.

A stock mixture was prepared in an argon purged and blanketed bottle.The stock mixture comprised 11.2 weight percent of dichlorosilane incyclopentene. A platinum divinylsiloxane complex providing a finalconcentration of platinum, based on dichlorosilane, as described inTable 3 (Pt ppm) was added to the stock mixture. Aliquots of thiscatalyzed stock solution were then transferred to argon-purged glasstubes and MBO was added at the concentrations described in Table 3. Theconcentration of MBO (% MBO) is given as a weight percent of the totalweight of the mixture. The tubes were then heat sealed under argon purgeand heated for the times and temperatures described in Table 3. At theend of the heating period the tubes were cooled to about roomtemperature and the contents analyzed by GC-TC. The results of thisanalysis are reported in Table 1 as the area percent under the GC-TCtrace for each addition product.

                                      TABLE 3                                     __________________________________________________________________________    2-Methyl-3-butyn-2-ol as Accelerator For Platinum                             Catalyzed Addition of H.sub.2 SiCl.sub.2 to Cyclopentene                      Pt                                                                            (ppm)                                                                             % MBO                                                                              T (min.)                                                                           °C.                                                                       CpH.sub.2 SiCl                                                                      CpHSiCl.sub.2                                                                       CpSiCl.sub.3                                                                       Cp.sub.2 HSiCl                                                                      Cp.sub.2 SiCl.sub.2                   __________________________________________________________________________     200                                                                              0.1  120  120                                                                              0.64  5.30  0.50 0.00  0.20                                   200                                                                              1.0  60   120                                                                              0.00  11.30 0.50 0.00  0.00                                  1000                                                                              0.5  30   120                                                                              0.27  12.60 0.60 0.10  0.60                                  1000                                                                              0.5  60   120                                                                              0.70  9.30  0.50 0.10  0.30                                  1000                                                                              0.5  120  120                                                                              o.s9  11.20 0.60 0.20  0.16                                  1000                                                                              1.0  60   120                                                                              0.00  0.00  0.00 0.00  11.50                                 2000                                                                              0.0  10    24                                                                              0.00  1.95  0.00 1.60  0.00                                  2000                                                                              1.0  10    24                                                                              0.00  13.80 0.60 0.00  0.00                                  2000                                                                              1.0  960   24                                                                              0.16  12.90 0.60 0.16  4.10                                  2000                                                                              1.0  15   120                                                                              0.00  1.79  1.30 0.45  13.00                                 2000                                                                              1.0  30   120                                                                              0.16  1.39  0.90 0.50  15.80                                 __________________________________________________________________________

In Table 3, Cp is cyclopentyl.

EXAMPLE 3

The ability of 2-methyl-3-butyn-2-ol (MBO) to accelerate the reaction ofmethyldichlorosilane with cyclooctene was evaluated.

A stock mixture was prepared in an argon purged and blanketed bottle.The stock mixture comprised 52 weight percent methyldichlorosilane incyclooctene which had been treated with 13X molecular seives. A platinumdivinylsiloxane complex was added to the stock mixture to provide aplatinum concentration of about 58 ppm in the stock mixture. Aliquots ofthis catalyzed stock mixture were then transferred to argon-purged glasstubes and MBO was added to provide a concentration of about 1 weightpercent of the total weight of the mixture. The tubes were then heatsealed under argon purge and heated at 120° C. for the times reported inTable 4. At the end of the heating period the tubes were cooled to aboutroom temperature and the contents analyzed by GC-TC. The results of thisanalysis are reported in Table 4 as the area percent under the GC-TCtrace for cyclohexylmethyldichlorosilane.

                  TABLE 4                                                         ______________________________________                                        2-Methyl-3-butyn-2-ol as Accelerator For Platinum                             Catalyzed Addition of MeHSiCl.sub.2 to Cyclooctene                            Time (h) MeC.sub.8 H.sub.15 SiCl.sub.2 (GC-TC Area Percent)                   ______________________________________                                        3.0      8.9                                                                  5.5      13.4                                                                 22.0     16.6                                                                 5.5*     2.7                                                                  ______________________________________                                         *Control-no accelerator added.                                           

We claim:
 1. A hydrosilation process comprising: contacting(A) a siliconhydride described by formula

    R.sup.1.sub.a H.sub.b SiCl.sub.4-a-b,

where each R¹ is independently selected from a group consisting ofalkyls comprising one to 20 carbon atoms, cycloalkyls comprising four to12 carbon atoms, and aryls; a=0 to 3, b=1 to 3, and a+b=1 to 4; and (B)an unsaturated reactant selected from a group consisting of(i)substituted and unsubstituted unsaturated organic compounds, (ii)silicon compounds comprising substituted or unsubstituted unsaturatedorganic substituents, and (iii) mixtures of (i) and (ii);in the presenceof a platinum catalyst selected from a group consisting of platinumcompounds and platinum complexes, and an accelerator selected from agroup consisting of acetylenic alcohols described by formulas ##STR5##silated acetylenic alcohols described by formulas ##STR6## acetylenicethers described by formulas ##STR7## where R² is selected from a groupconsisting of hydrogen, hydroxyl, substituted and unsubstituted alkylscomprising one to 20 carbon atoms, and substituted and unsubstitutedalkoxys comprising one to 20 carbon atoms, each R³ is independentlyselected from a group consisting of hydrogen, alkyls comprising one to20 carbon atoms, cycloalkyls comprising four to 20 carbon atoms, andaryls; each R⁴ is an independently selected alkyl of cycloalkylcomprising no more than 20 carbon atoms, R⁵ is selected from a groupconsisting of monovalent hydrocarbon radicals comprising one to 20carbon atoms and heterocyclic hydrocarbon radicals having a carbon tooxygen bond, each R6 is independently selected from a group consistingof hydrogen and R¹, c=0 to 3, d=0 to 3, c+d=0 to 3, e=1 to 4, f=0 to 10,and n=4 to
 12. 2. A process according to claim 1, where each R¹ isindependently selected from a group consisting of alkyls comprisingabout one to six carbon atoms.
 3. A process according to claim 1, wherethe silicon hydride is selected from a group consisting oftrimethylsilane, dimethylsilane, triethylsilane, dichlorosilane,trichlorosilane, methyldichlorosilane, dimethylchlorosilane,ethyldichlorosilane, cyclopentyldichlorosilane,methylphenylchlorosilane, and (3,3,3-trifluoropropyl)dichlorosilane. 4.A process according to claim 1, where the silicon hydride is selectedfrom a group consisting of methyldichlorosilane and dichlorosilane.
 5. Aprocess according to claim 1, where the unsaturated reactant is selectedfrom a group consisting of unsubstituted cycloalkene compoundscomprising at least four carbon atoms, substituted cycloalkene compoundscomprising at least four carbon atoms, linear alkene compoundscomprising about two to 30 carbon atoms, and branched alkene compoundscomprising four to about 30 carbon atoms.
 6. A process according toclaim 1, where the unsaturated reactant is selected from a groupconsisting of cyclohexene and cyclopentene.
 7. A process according toclaim 1, where the unsaturated reactant is cyclohexene.
 8. A processaccording to claim 1, where the process is run with about 0.1 to tenpercent stoichiometric excess of silicon hydride relative to unsaturatedcarbon-carbon linkages of the unsaturated reactant.
 9. A processaccording to claim 1, where the platinum catalyst is selected from agroup consisting of chloroplatinic acid, chloroplatinic acidhexahydrate, and platinum divinylsiloxane complexes.
 10. A processaccording to claim 1, where the platinum catalyst is a platinumdivinylsiloxane complex.
 11. A process according to claim 1, where theplatinum catalyst is added to the process at a concentration whichprovides about one to 1000 moles of platinum per 1×10⁶ moles ofunsaturated carbon-carbon bonds provided to the process by theunsaturated reactant.
 12. A process according to claim 1, wheresubstituent R² of the accelerator is selected from a group consisting ofhydrogen and alkyls comprising about one to six carbon atoms.
 13. Aprocess according to claim 1, where substituent R² of the accelerator isselected from a group consisting of hydrogen, methyl, ethyl, propyl,iso-butyl, 1-methyl-l-hydroxyethyl, and hexyl.
 14. A process accordingto claim 1, where substituent R² of the accelerator is hydrogen.
 15. Aprocess according to claim 1, where each substituent R³ of theaccelerator is independently selected from a group consisting ofhydrogen, alkyls comprising one to six carbon atoms, and phenyl.
 16. Aprocess according to claim 1, where substituent R⁴ of the accelerator isselected from a group consisting of methyl and cyclopentyl.
 17. Aprocess according to claim 1, where substituent R⁵ of the accelerator isselected from a group consisting of methyl, ethyl, tert-butyl,cyclopentyl, cyclohexyl, phenyl, naphthyl, and tetrahydrofuranyl.
 18. Aprocess according to claim 1, where the accelerator is selected from agroup consisting of 2-methyl-3-butyn-2-ol, silated2-methyl-3-butyn-2-ol, 1 ethynyl-1-cyclohexanol, and 3,3-dimethyl-1-hexyn-3-ol.
 19. A process according to claim 1, whereconcentration of the accelerator is within a range of about 0001 to 20weight percent on the weight of the unsaturated reactant.
 20. A processaccording to claim 1, where concentration of the accelerator is within arange of about 0.1 to ten weight percent of the weight of theunsaturated reactant.
 21. A process according to claim 1, where theprocess is conducted at a temperature within a range of about -10° C. to220° C.
 22. A process according to claim 1, where the process isconducted at a temperature within a range of about 30° C. to 150° C.